Hi Sonya- sounds like a project the kids could get into.

Here's your difficulty: soldering to the arbor would be problematic because the mass of metal would carry off heat faster than the soldering iron or propane torch could pour it on. So you need a heat source that can supply a lot of concentrated heat. Plumbers who work with copper pipe use those little butane/oxygen torches, I think, because they get much hotter than propane. That would probably work on your arbor. (Of course, any heat source is going to blister paint, etc., so make sure you have good ventilation.) And some stuff is just not going to solder for you. Aluminum, for example, will form an oxidation layer as it approaches soldering heat, and a bond will not form. I doubt a soldering iron would work unless it were a very big and heavy one.

You might consider some of the products such as JD Weld, that glue things together. These actually work, sometimes surprisingly well.

Be sure to clean surfaces with sandpaper or some such, make sure they contact each other well, and have a way to hold them in place while you heat both pieces enough to melt your acid-core solder. When both pieces are hot touch the solder to the point where the pieces join and the flux will melt and flow into the joint and the solder will immediately follow it. Remove the heat, and allow to cool.Have fun! It sounds like a great project for kids.

Thanks for the ideas. As I said...I've got this summer to work out the issues. I do think I'll look into JD Weld or something similar and see how that holds up. Appreciate your help. Maybe NEXT summer I'll take that welding course...